Printed circuit boards are interconnected to other circuit devices and equipments by forming contact pads along one or more edge sections of the boards and contacting these pads with terminals projecting from a connector housing. In some instances the connector terminals are permanently secured to the pads by coating the pads with solder, engaging the terminals with the pads, and reflowing the solder. In such operations great care must be exercised to insure that each terminal engages only one corresponding contact pad.
The problem is particularly acute in manufacturing large size circuit boards with large numbers of closely spaced small contact pads formed on both the upper and underside of the board that are engaged by two arrays of closely spaced thin spring wire connector terminals. Inasmuch as the contact pads project from the surface of the circuit board, there are formed discrete grooves between each pair of pads. When assembling the connector with the board, there is a tendency for the spring-type terminals to fall from the contact pads and into the grooves, or ride into the grooves during the initial assembly of the connector onto the board.
In some instances, a terminal may be positioned in a groove without engaging either of its adjacent contact pads. In such case, a subsequent reflow soldering operation is ineffective to secure such a terminal to its corresponding contact pad. Also, if a terminal is positioned askew of a pair of contact pads, an ensuing reflow soldering operation would result in the securing of the terminal in bridging relation to two adjacent contact pads. In other instances, a pair of connector terminals may fall within a groove while engaging portions of adjacent contact pads so that the subsequent reflow solder operation functions to establish a conductive bridge between adjacent contact pads. Prior to the reflow soldering of these boards, it is necessary that the terminals positions be visually checked and, as required, the terminals must be manually repositioned to overlie individual contact pads. These operations are very tedious and exacting, requiring a substantial amount of shop time and operator handling.
Therefore, there exists a need for a fast, acurate, as well as, reliable quasi-automated technique for achieving the foregoing reflow soldering of the terminals onto the board while minimizing the need for operator intervention.